such as falls greater than 30 feet or an MVC greater than

30 mph, should raise concern for potential vascular shearing

injuries. With penetrating trauma, the type of stabbing

implement should be ascertained.

� Physical Examination

An assessment of patient vital signs is the cornerstone of

the primary survey. Progressive sinus tachycardia and sys ­

temic hypotension indicates a serious cardiovascular

derangement that should be addressed immediately.

Significant hypoxia could indicate an underlying pulmonary contusion, HT X, or PT X.

Inspection of the patient's neck might reveal jugular

venous distension indicative of pericardia! tamponade or

tension PT X or tracheal deviation indicative of an evolving

tension PT X. Examination of the thorax should begin with

gross observation. Chest wall asymmetry with regional

paradoxical movement during respiration indicates

underlying flail chest. A large open defect in the chest wall

with audible air movement during respiration indicates a

communicating PT:x. Penetrating wounds either located

within or transecting the "cardiac box" are most likely to

involve the heart and surrounding mediastinal structures

and require a more extensive work-up. T he anterior cardiac

box is defined as the region medial to the nipples extending

between the suprasternal notch and xiphoid process. T he

posterior cardiac box is defined as the region between the

medial borders of the scapulae extending from the superior

border of the scapulae to the costal margin (Figure 87-1).

Palpation of the chest wall can detect point tenderness

indicative of an underlying fracture of the thoracic cage or

soft tissue crepitus suggestive of an underlying PTX or

tracheobronchial injury.

Auscultation of the chest will reveal absent or diminished

breath sounds indicative of an underlying PTX or HT X,

whereas inspiratory crackles suggests an evolving pulmonary

contusion. Diminished heart sounds are heard in patients

with pericardia! bleeding and potential cardiac tamponade.

Patients with significant thoracic trauma often have

concomitant abdominal injuries. A careful examination

of the upper abdomen should be performed in patients

with fractures of the lower ribs due to the potential for

contusion or laceration of the underlying liver or spleen.

Finally, distal pulses should be assessed, as marked

asymmetry could indicate significant vascular injury.

CHAPTER 87

A

B

Figure 87-1. A, B. Anterior and posterior cardiac box.

DIAGNOSTIC STUDIES

..... Laboratory

There are no laboratory studies specific to the work-up of

patients with thoracic trauma. Typical studies obtained

include a complete blood count, electrolyte panel with r enal

function, serum and urine toxicology studies including an

ethanol level, a serum lactate level, and a serum base deficit.

These tests should be used primarily to determine the

severity of the traumatic insult and the adequacy of the

patient's physiologic response.

.... Imaging

All thoracic trauma patients, both blunt and penetrating,

require an initial screening chest x-ray (CJCR) . Sternal

and rib fractures are often difficult to detect, with -50%

missed on the initial CXR. This is especially true for fractures of the anterior and lateral portions of the first 5 r ibs

and sternal fractures when a lateral view is not obtained.

Fortunately, it is the potential injury to any underlying

structures that is of clinical significance. Pulmonary contusions will appear as focal opacifications within the lung

parenchyma and typically manifest within the first

6 hours of presentation. A simple pneumothorax will

appear as free air within the intrapleural space with an

adjacent visible edge of visceral pleura. A good rule of

thumb is that a PTX of 2.5 em in an adult indicates a 40%

loss of lung volume. Penetrating thoracic trauma patients

with a normal initial CXR typically require repeat imaging several hours later to rule out the development of a

delayed PTX. An HTX can be visualized on an upright

CXR once -200 mL of blood has accumulated and will

initially appear as blunting of the ipsilateral costophrenic

angle (Figure 87-2). On a supine CXR, a large HTX will

appear as a diffuse haziness of the entire hemithorax due

to posterior layering of the free-flowing intrapleural

blood. Finally, chest radiography can be used as a screening study for BAl. Concerning findings include a widened

superior mediastinum (>8 em), an indistinct or obscured

aortic knob, rightward displacement of an intraesophageal

nasogastric tube, inferior displacement of the left

mainstem bronchus, or an apical pleural cap (Figure 87-3).

Because of a false-negative rate of -10%, a normal initial

CXR cannot reliably exclude BAl.

.&. Figure 87-2. Right-sided hemopneumothorax. Note

the absence of lung markings in the right hemithorax,

radio-opaque collapsed lung tissue adjacent to the right

hilum, blunting of the costophrenic angle due to blood

in the intrapleural space, and air fluid level pathognomonic for a hemopneumothorax. Reprinted with permission from Young Jr. WF. Chapter 71 . Spontaneous and

Iatrogenic Pneumothorax. In: Tintinalli JE, Stapczynski JS,

Cline OM, Ma OJ, Cydulka RK, Meckler GO, eds. Tintinalli's

Emergency Medicine: A Comprehensive Study Guide.

7th ed. New York: McGraw-Hill, 201 1.

THORACIC TRAUMA

Figure 87-3. Blunt aortic injury on CXR . Note

the widened superior mediastinum (a rrows).

A standard 1 2-lead electrocardiogram (ECG) is the

initial study of choice to work up patients with potential

BMI. Because of its anterior location within the chest, the

right ventricle is the most likely structure affected. Expected

findings include ST-segment changes and/or T-wave

inversions (typically in the inferior and anterior leads),

conduction delays, and dysrhythrnias. A normal initial

ECG in an asymptomatic individual reliably excludes any

future complications of BMI. A bedside echocardiogram

(ECHO) can be a useful adjunct in patients with presumed

symptomatic BMI and may demonstrate focal regions of

myocardial contusion that have the potential to progress to

subsequent cardiogenic shock. Furthermore, ECHO is

indicated in the work-up of any patient with penetrating

trauma to the cardiac box, with aq ualifiedechocardiographer

able to detect accumulations of blood as little as 20 mL

within the pericardia! sac (Figure 87-4). Finally, bedside

ultrasound (US) does have a role in helping to diagnose

PTX and can detect HTX with a volume as low as 50 mL.

Computed tomography angiography ( CTA) has become

the modality of choice in evaluating patients with potential

BAI (Figure 87-5). Because of the high lethality associated

with delayed diagnosis, any patient with a sudden deceleration mechanism (fall >30 ft or MVC >30 mph) and either

an abnormal CXR or evidence of thoracic injury should

undergo CTA. Given improvements in CTA technology, a

normal study is essentially 1 00% sensitive to exclude BAl.

PROCEDURES

...... Needle and Tube Thoracostomy

Needle decompression of a tension PTX is an emergently

life-saving procedure and should be performed during the

primary survey. Chest tube placement should be used for the

management of nearly every traumatic PTX or HTX. See

Chapter 7 for further details.

A Figure 87-4. Traumatic pericardia! effusion on bedside FAST exam. Note the large collection of fluid

with in the pericardia! space (arrow). Reprinted with

permission from Ross C, Schwab TM. Chapter 259.

Cardiac Trauma. In: Tintinalli JE, Stapczynski JS, Cline

DM, Ma OJ, Cydulka RK, Meckler GD, eds. Tintinalli's

Emergency Medicine: A Comprehensive Study Guide.

7th ed. New York: McGraw-Hill, 201 1.

Figure 87-5. Blunt aortic injury on CTA. Note

the disrupted aortic lumen at the attachment site

of the ligamentum arteriosum (a rrow).

...... Pericardiocentesis

Pericardiocentesis can be an emergently life-saving

procedure for any patient exhibiting peri car dial tamponade.

A long large-gauge needle (eg, a 10-cm 18-gauge spinal

needle) should be inserted at the subxiphoid space and

directed toward the underlying pericardium. US guidance

CHAPTER 87

can facilitate proper placement. Aspiration of volumes as

low as 10 mL of pericardia! blood result in stroke volume

increases between 25% and 50% and can stabilize the

patient pending definitive operative treatment .

...... ED Thoracotomy

A resuscitative thoracotomy can be a life-saving procedure

when performed on patients who lose signs of life either

with EMS in route or in the ED. In the best possible circumstances, survival rates are <10% and usually highest

for victims of penetrating trauma, especially those with

anterior stab wounds. Once the decision is made to per ­

form an ED thoracotomy, the procedure should be done

expediently without delay. An incision should be made in

the fourth or fifth intercostal space extending from the

sternal border to the posterior axillary line. The intercostal

muscles are incised and the ribs are retracted to expose the

underlying thoracic viscera. The pericardium can be visualized by gently retracting the overlying lung, and any

pericardia! blood will be apparent. The pericardium should

be opened with a vertical incision (to avoid trauma to the

nearby phrenic nerves) and the heart lifted forward and

"delivered" from the pericardia! sac. Cardiac wounds are

treated either with suture or staple closure (with care being

made to avoid occluding an underlying coronary artery) or

Foley catheter balloon tamponade. If the patient fails to

respond, the descending aorta should be cross-clamped to

direct any subsequent cardiac output into the cerebral and

cardiopulmonary circulation.